MathRevolution wrote:
Machine A can do a job in 24 hours at a constant rate. If Machine A does the job for 8 hours and Machine B does the rest of the job, which works at 2/3 constant rate of Machine A. How long will it take for Machine B alone to do the rest of the job?
A. 12hrs
B. 16hrs
C. 24hrs
D. 28hrs
E. 32hrs
The rate of machine A is 1/24, so in 8 hours 1/3 of the job is completed, and thus 2/3 of the job is left to be completed.
If the rate of machine B is 2/3 that of machine A, then
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